The fluorescent lighting used in many office buildings and similar structures usually comprises long (for example, four to eight feet in length, fixtures that mount one or more fluorescent tubes. Because the lamps operate from a gaseous discharge, a ballast is required. The ballast provides circuitry that controls the electrical current through the lamp during its startup and subsequent operation. For many years it has been the practice to “hardwire” the ballast into the system. Thus, while it is possible to replace a lamp or lamps without shutting off the main power supply, because the ballasts were hardwired into the system replacement necessitated deactivating the complete power supply, usually at the mains, which causes a good deal of unnecessary disruption.